Carl moldenhauer



UNITED STATES PATENT OFFICE.

CARL MOLDENHAUER, OF FRANKFORT-ON-TI-IE-MAIN, GERMANY.

PROCESS OF EXTRACTING GOLD FROM ITS ORES.

SPECIFICATION forming part of Letters Patent No. 483,766, dated October 4, 1892.

Application filed February 20, 1892. Serial No. 422,294. (No specimens.)

To all whom it may concern.-

Be it known that I, CARL MOLDENHAUER, a subject of the Emperor of Germany, and a resident of Frankfort-on-the-lliain, Germany,

have invented new and useful Improvements in the Process of Obtaining Precious Metals from Ores, of which the following is a specification.

This invention relates to the process of extracting gold from its ores by means of a solution of cyanide of potassium, and has for its object to render the process more expeditious and considerably cheaper.

In extracting gold from its ores by means of a solution of cyanide of potassium the simultaneous oxidation of the gold is necessary, and this has hitherto been efiected by the action of the air upon the gold, which is rendered oxidizable thereby by the action of the cyanide solution. Instead of depending upon the agency of the air for the oxidizing action I oxidize the gold by the addition to the said cyanide solution of permanganate of potas sium, which is an oxidizing agent not essentially affected by the cyanide of potassium.

The process is preferably carried out in a ball-mill lined with porcelain, wood, or other substance unattackable by the chemicals employed.

I do not claim, broadly, as my invention the dissolution of gold from its ores by means of cyanide of potassium; but

hat I claim as my invention, and desire to secure by Letters Patent, is-

The process herein described of extracting gold from its ores, consisting in subjecting the ores to the dissolving action of cyanide of potassium in the presence of permanganate of potassium, substantially as herein described.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

CARL MOLDENHAUER.

\Vi tnesses:

FRANZ HAPLACHER, FRIEDRICH OoREELL. 

